1. Field of the Invention
This invention relates to a magnetic recording medium such as video tape, audio tape or computer tape and more particularly, it is concerned with a magnetic recording medium having an improved abrasion resistance.
2. Description of the Prior Art
In a magnetic recording medium which has commonly been used at present, a ferromagnetic powder is dispersed in a binder of thermoplastic resin such as vinyl chloride-vinyl acetate resins, vinyl chloride-vinylidene chloride resins, cellulose resins, acetal resins, urethane resins, acrylonitrile-butadiene resins and the like, individually or in combination, and coated onto a support member such as polyethylene terephthalate, cellulose triacetate, polyvinyl chloride and the like to form a magnetic layer. This magnetic layer has a drawback that the abrasion resistance is inferior so that a running path of a magnetic tape is contaminated.
For the purpose of forming a binder layer excellent in abrasion resistance, it has hitherto been proposed to use thermosetting resins such as melamine resin, urea resin and the like, or to add binders capable of bridge making through chemical reactions, such as isocyanate compounds, epoxy compounds and the like to the above described thermoplastic resins. However, even if such bridge making binders are added, a long time has been taken until the finish of the reaction.